A rare combination of correct transposition of the great arteries and isolated levocardia: Imaging characterization.

Congenitally correct transposition of the great arteries (cc-TGA) is an extremely rare congenital cardiac malposition. It can be detected antenatally by echocardiography. This case report describes a 58-year-old female patient who presented with tachycardia. The combination of cc-TGA and isolated levocardia is incidentally diagnosed by transthoracic echocardiography and cardiac magnetic resonance imaging.

Modified Senning Procedure for Treatment of Transposition of the Great Arteries with Crisscross Heart.

CLINICAL DATA: A nine-month-old female infant diagnosed with transposition of the great arteries with symptoms of heart failure associated with cyanosis and difficulty in gaining weight was referred to our center with late diagnosis (at nine months of age). CHEST RADIOGRAPHY: Cardiomegaly; attenuated peripheral vascular markings.Electrocardiography: Sinus rhythm with biventricular overload and aberrantly conducted supraventricular extra systoles. ECHOCARDIOGRAPHY: Wide atrial septal defect, ventricular axis torsion with concordant atrioventricular connection and discordant ventriculoarterial connection. COMPUTED TOMOGRAPHY ANGIOGRAPHY: Concordant atrioventricular connection, right ventricle positioned superiorly and left ventricle positioned inferiorly; discordant ventriculoarterial connection with right ventricle connected to the aorta and left ventricle connected to pulmonary artery. DIAGNOSIS: Crisscross heart is a rare congenital heart defect, accounting for 0.1% of congenital heart diseases. It consists of the 90º rotation of ventricles' axis in relation to their normal position; therefore, ventricles are positioned in the superior-inferior direction rather than anterior-posterior. Most cases have associated cardiac anomalies, and in this case, it is associated with transposition of the great arteries. The complexity and rarity of its occurrence make diagnosis and surgical treatment challenging. OPERATION: Modified Senning procedure using the pericardial sac in the construction of a tunnel from pulmonary veins to the right atrium. Cardiopulmonary bypass time of 147 minutes with nine minutes of total circulatory arrest.

Human Genetics of d-Transposition of Great Arteries.

Although several genes underlying occurrence of transposition of the great arteries have been found in the mouse, human genetics of the most frequent cyanotic congenital heart defect diagnosed in neonates is still largely unknown. Development of the outflow tract is a complex process which involves the major genes of cardiac development, acting on myocardial cells from the anterior second heart field, and on mesenchymal cells from endocardial cushions. These genes, coding for transcription factors, interact with each other, and their differential expression conditions the severity of the phenotype. A precise description of the anatomic phenotypes is mandatory to achieve a better comprehension of the complex mechanisms responsible for transposition of the great arteries.

Molecular Pathways and Animal Models of d-Transposition of the Great Arteries.

During normal cardiovascular development, the outflow tract becomes septated and rotates so that the separate aorta and pulmonary trunk are correctly aligned with the left and right ventricles, respectively. However, when this process goes wrong, the aorta and pulmonary trunk are incorrectly positioned, resulting in oxygenated blood being directly returned to the lungs, with deoxygenated blood being delivered to the systemic circulation. This is termed transposition of the great arteries (TGA). The precise etiology of TGA is not known, but the use of animal models has elucidated that genes involved in determination of the left- embryonic body axis play key roles. Other factors such as retinoic acid levels are also crucial. This chapter reviews the animal models presenting with TGA that have been generated by genetic manipulation or with exogenous agents.

Clinical Presentation and Therapy of d-Transposition of the Great Arteries.

d-Transposition of the great arteries (d-TGA) is the most common form of congenital heart disease that presents with cyanosis in a newborn. The aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle. It constitutes 3-5% of all congenital heart defects. In a simple d-TGA (about two-thirds of patients), there is no other cardiac abnormality other than a patent foramen ovale (PFO) and a patent ductus arteriosus (PDA). In a complex d-TGA additional cardiac abnormalities such as VSD, pulmonary stenosis or coronary abnormalities are present. About one-third to 40% of patients with d-TGA have an associated ventricular septal defect. Among patients with d-TGA, 6% of those with intact ventricular septum and 31% of those with ventricular septal defect have associated pulmonary stenosis. Coronary abnormalities are of importance with regard to the complexity of surgical repair.

Pulmonary, aorta, and coronary arteries post-arterial switch in transposition of great arteries: intermediate-term surveillance utilizing conventional echocardiography and cardiac multislice computed tomography.

BACKGROUND: Arterial switch operation (ASO) is the standard surgical choice for D-transposition of great arteries (D-TGA). However, the implications of ASO on pulmonaries, coronaries, and aorta have not been adequately investigated. The current study evaluates arterial morphologic changes post-ASO at intermediate-term surveillance. METHODS: From May 2021 to May 2022, patients with D-TGA who underwent ASO for more than six months were recruited. Preoperative and operative data were collected. Patients were assessed using echocardiography (ECHO) and multislice CT angiography (MSCT) to evaluate pulmonary, coronary, and aortic arterial anatomy. RESULTS: Twenty patients were included with median age of 11 (10-23.25) days at ASO and 14 (7.25-32.75) months on last follow-up. Neo-aortic regurgitation was detected in 12(60%) and neo-pulmonary regurgitation in 3 (15%). Using ECHO, complete evaluation of pulmonary arteries (PAs) was not achieved in 35% and incomplete coronaries assessment in 40% of cases. No stenosis was detected in coronaries using MSCT, although coronary anomalies were found in 9/20 (45%). Dilated Aortic annulus was detected in 16/20 (80%), dilated aortic root in 18/20 (90%), and dilated sinotubular junction in 70%. Right PA stenosis was diagnosed in 10/20 (50%) and left PA(LPA) stenosis in 7/20 (35%). Although Z-score of PAs did not correlate with aortic data, LPA bending angle was positively correlated to neo-aortic root diameter and Z-score (rho = 0.65,p = 0.016; rho = 0.69,p = 0.01), respectively. CONCLUSION: Echocardiography alone is not a conclusive surveillance tool for detecting late post-ASO anatomic changes in D-TGA patients. Cardiac MSCT should be considered for comprehensive evaluation on the intermediate-term follow-up post-ASO to accurately track morphologic abnormalities in the aorta, pulmonary, and coronary arteries.

Arterial switch operation in a child with commissural malalignment and unusual coronary anatomy.

The arterial switch operation has evolved to become the treatment of choice for transposition of the great arteries and is one of the greatest success stories in congenital heart surgery. The most crucial step of the operation is the coronary artery translocation; therefore, it is of paramount importance for surgeons to know every single detail about the morphology and spatial relationships of the coronary arteries and the roots of the great vessels. However, sometimes the surgeon may face unfavourable scenarios such as major commissural malalignment and anomalous coronary artery patterns and need to be prepared to carry out a successful coronary artery translocation. Herein, we demonstrate that the trapdoor technique is useful for transferring coronary arteries in a neonate with major commissural malalignment and unusual coronary anatomy during the arterial switch operation.

Lead Extraction and Baffle Stenting in a Patient with Transposition of the Great Arteries.

This case report discusses a 42-year-old male with dextro-transposition of the great arteries (D-TGA) status post Mustard repair and sick sinus syndrome status post dual-chamber pacemaker implant, who developed symptomatic superior vena cava (SVC) baffle stenosis. He was treated with a combined pacemaker extraction and subsequent SVC baffle stenting. The case highlights the complexities of treating SVC baffle stenosis in the presence of cardiac implantable devices and demonstrates the efficacy of this combined approach. Furthermore, the authors delve into the intricacies of D-TGA, its surgical history, and the long-term complications associated with atrial switch procedures.

Half-turned truncal switch operation for dextro-transposition of the great arteries with ventricular septal defect and left ventricular outflow tract obstruction and an abnormal coronary pattern.

We describe a surgical technique for a half-turned truncal switch operation in a 5-year-old child with dextro-transposition of the great arteries (D-TGA), a ventricular septal defect, a left ventricular outflow tract obstruction and a complex coronary pattern. The benefit of the half-turned truncal switch is the creation of haemodynamically superior biventricular outflow tracts and the maximal use of an autologous pulmonary valve in the right ventricular outflow tract, thereby avoiding the right ventricular-pulmonary artery conduit.

Fetal left and right ventricular strain parameters using speckle tracking in congenital heart diseases.

Assessment of fetal ventricular function is mostly subjective, and currently, for the objective assessment left ventricular shortening fraction is obtained. However, this by itself is not very reliable. Hence, more tools that can provide an objective assessment are needed to increase the confidence of functional assessment. Speckle tracking imaging can provide one such tool. In this study we sought to establish the normative value of global longitudinal and circumferential strain for our fetal patients and for two major forms of congenital heart diseases, namely atrioventricular canal defects (AVC) and uncorrected dextro-transposition of the great arteries (dTGA) to act as a benchmark. The study was completed via a single center retrospective analysis on 72 fetal echocardiograms (26 normal, 15 dTGA, and 31 AVC). Tomtec Arena™ echocardiography analysis software was used for analysis. In normal fetuses, mean left ventricular (LV) global longitudinal strain (GLS) was - 22.6% (95% CI -24, -21.1) and mean right ventricular (RV) GLS was - 22.1% (95% CI -23.6, -20.6). In AVC patients LV GLS was-26.6% (95% CI -28,-25.3) and mean RV GLS was - 26.5% (95% CI -27.9,-25.2). In dTGA patients LV GLS was - 22.9% (95% CI of -24.8, -21) and RV GLS was - 21.3% (95% CI was - 23.4, -20.8). There was good intra-rater reliability though poor to fair inter-rater reliability. Notwithstanding its current limitations, strain imaging can provide useful information that can increase confidence of cardiac functional assessment in fetal patients. However, to be reliable across the board, further automation and standardization is required.

NODAL variants are associated with a continuum of laterality defects from simple D-transposition of the great arteries to heterotaxy.

BACKGROUND: NODAL signaling plays a critical role in embryonic patterning and heart development in vertebrates. Genetic variants resulting in perturbations of the TGF-ß/NODAL signaling pathway have reproducibly been shown to cause laterality defects in humans. To further explore this association and improve genetic diagnosis, the study aims to identify and characterize a broader range of NODAL variants in a large number of individuals with laterality defects. METHODS: We re-analyzed a cohort of 321 proband-only exomes of individuals with clinically diagnosed laterality congenital heart disease (CHD) using family-based, rare variant genomic analyses. To this cohort we added 12 affected subjects with known NODAL variants and CHD from institutional research and clinical cohorts to investigate an allelic series. For those with candidate contributory variants, variant allele confirmation and segregation analysis were studied by Sanger sequencing in available family members. Array comparative genomic hybridization and droplet digital PCR were utilized for copy number variants (CNV) validation and characterization. We performed Human Phenotype Ontology (HPO)-based quantitative phenotypic analyses to dissect allele-specific phenotypic differences. RESULTS: Missense, nonsense, splice site, indels, and/or structural variants of NODAL were identified as potential causes of heterotaxy and other laterality defects in 33 CHD cases. We describe a recurrent complex indel variant for which the nucleic acid secondary structure predictions implicate secondary structure mutagenesis as a possible mechanism for formation. We identified two CNV deletion alleles spanning NODAL in two unrelated CHD cases. Furthermore, 17 CHD individuals were found (16/17 with known Hispanic ancestry) to have the c.778G > A:p.G260R NODAL missense variant which we propose reclassification from variant of uncertain significance (VUS) to likely pathogenic. Quantitative HPO-based analyses of the observed clinical phenotype for all cases with p.G260R variation, including heterozygous, homozygous, and compound heterozygous cases, reveal clustering of individuals with biallelic variation. This finding provides evidence for a genotypic-phenotypic correlation and an allele-specific gene dosage model. CONCLUSION: Our data further support a role for rare deleterious variants in NODAL as a cause for sporadic human laterality defects, expand the repertoire of observed anatomical complexity of potential cardiovascular anomalies, and implicate an allele specific gene dosage model.

External Validation of a Risk Score Model for Predicting Major Clinical Events in Adults After Atrial Switch.

BACKGROUND: A risk model has been proposed to provide a patient individualized estimation of risk for major clinical events (heart failure events, ventricular arrhythmia, all-cause mortality) in patients with transposition of the great arteries and atrial switch surgery. We aimed to externally validate the model. METHODS AND RESULTS: A retrospective, multicentric, longitudinal cohort of 417 patients with transposition of the great arteries (median age, 24 years at baseline [interquartile range, 18-30]; 63% men) independent of the model development and internal validation cohort was studied. The performance of the prediction model in predicting risk at 5 years was assessed, and additional predictors of major clinical events were evaluated separately in our cohort. Twenty-five patients (5.9%) met the major clinical events end point within 5 years. Model validation showed good discrimination between high and low 5-year risk patients (Harrell C index of 0.73 [95% CI, 0.65-0.81]) but tended to overestimate this risk (calibration slope of 0.20 [95% CI, 0.03-0.36]). In our population, the strongest independent predictors of major clinical events were a history of heart failure and at least mild impairment of the subpulmonary left ventricle function. CONCLUSIONS: We reported the first external validation of a major clinical events risk model in a large cohort of adults with transposition of the great arteries. The model allows for distinguishing patients at low risk from those at intermediate to high risk. Previous episode of heart failure and subpulmonary left ventricle dysfunction appear to be key markers in the prognosis of patients. Further optimizing risk models are needed to individualize risk predictions in patients with transposition of the great arteries.

Fetal transposition of the great arteries: 3D virtual and physical models from ultrasound datasets.

Transposition of the great arteries (TGA) is a cyanotic congenital heart disease characterized by ventriculoarterial discordance and atrioventricular concordance with the great arteries in a parallel relationship. Prenatal diagnosis of TGA has implications for postnatal outcomes, allowing for planned delivery and perinatal management. Three-dimensional virtual or physical models of fetal TGA allow better understanding of fetal cardiac anomalies by parents and interactive discussion among the multidisciplinary team (obstetricians, pediatricians, maternal-fetal specialists, pediatric cardiologists, and cardiovascular surgeons), as well as continuing medical education.

Decreased clinical performance in TGA-ASO patients after RVOT interventions; a multicenter European collaboration.

BACKGROUND: In patients with transposition of the great arteries and an arterial switch operation (TGA-ASO) right ventricular outflow tract (RVOT) obstruction is a common complication requiring one or more RVOT interventions. OBJECTIVES: We aimed to assess cardiopulmonary exercise capacity and right ventricular function in patients stratified for type of RVOT intervention. METHODS: TGA-ASO patients (≥16 years) were stratified by type of RVOT intervention. The following outcome parameters were included: predicted (%) peak oxygen uptake (peak VO2), tricuspid annular plane systolic excursion (TAPSE), tricuspid Lateral Annular Systolic Velocity (TV S'), right ventricle (RV)-arterial coupling (defined as TAPSE/RV systolic pressure ratio), and N-terminal proBNP (NT-proBNP). RESULTS: 447 TGA patients with a mean age of 25.0 (interquartile range (IQR) 21-29) years were included. Patients without previous RVOT intervention (n = 338, 76%) had a significantly higher predicted peak VO2 (78.0 ± 17.4%) compared to patients with single approach catheter-based RVOT intervention (73.7 ± 12.7%), single approach surgical RVOT intervention (73.8 ± 28.1%), and patients with multiple approach RVOT intervention (66.2 ± 14.0%, p = 0.021). RV-arterial coupling was found to be significantly lower in patients with prior catheter-based and/or surgical RVOT intervention compared to patients without any RVOT intervention (p = 0.029). CONCLUSIONS: TGA patients after a successful arterial switch repair have a decreased exercise capacity. A considerable amount of TGA patients with either catheter or surgical RVOT intervention perform significantly worse compared to patients without RVOT interventions.

Repair of complex transposition of great arteries: What is the best technique to avoid outflow tract obstructions?

OBJECTIVES: This study aimed to evaluate the short-/mid-term outcome of patients with complex dextro (d)-/levo (l)-transposition of the great arteries (TGA), ventricular septal defect and left ventricular outflow tract obstructions. METHODS: A single-centre, retrospective review of all complex dextro-TGA (n = 85) and levo-TGA (n = 22) patients undergoing different surgeries [Arterial switch operation + left ventricular outflow tract obstruction-resection (ASO-R), half-turned truncal switch/Mair (HTTS), Nikaidoh and Rastelli] between May 1990 and September 2022 was performed. Groups were analysed using Kruskal-Wallis test with post hoc pairwise comparison and Kaplan-Meier time-to-event models. RESULTS: A total of 107 patients [ASO-R (n = 20), HTTS (n = 23), Nikaidoh (n = 21), Rastelli (n = 43)] were included, with a median age of 1.0 year (0.5-2.5) and surgical repair median follow-up was 3.8 years (0.3-10.5). Groups did not differ in respect to early postoperative complications/early mortality. Five-year overall survival curves were comparable: ASO-R 78.9% (53.2-91.5), HTTS 75.3% (46.8-89.9), Nikaidoh 85% (60.4-94.9) and Rastelli 83.9% (67.5-92.5), P = 0.9. Highest rates of right ventricular outflow tract (RVOT) reinterventions [33.3% and 32.6% (P = 0.04)] and reoperations [28.6% and 32.6% (P = 0.02)] occurred after Nikaidoh and Rastelli procedures. However, overall freedom from RVOT reinterventions and RVOT reoperations at 5 years did not differ statistically significantly between the groups (ASO-R, HTTS, Nikaidoh and Rastelli): 94.4% (66.6-99.2), 69.1% (25.4-90.5), 67.8% (34-86.9), 64.4% (44.6-78.7), P = 0.2, and 90.0% (65.6-97.4), 91% (50.8-98.7), 65.3% (32.0-85.3) and 67.0% (47.4-80.6), P = 0.3. CONCLUSIONS: Surgical repair of complex dextro-/levo-TGA can be performed with satisfying early/mid-term survival. RVOT reinterventions/reoperations were frequent, with highest rates after Nikaidoh and Rastelli procedures. Left ventricular outflow tract obstruction reoperations were rare with zero events after Nikaidoh and HTTS procedures.

The impact of unilateral pulmonary artery stenosis on right ventricular to pulmonary arterial coupling in patients with transposition of the great arteries.

BACKGROUND: Unilateral pulmonary artery (PA) stenosis is common in the transposition of the great arteries (TGA) after arterial switch operation (ASO) but the effects on the right ventricle (RV) remain unclear. AIMS: To assess the effects of unilateral PA stenosis on RV afterload and function in pediatric patients with TGA-ASO. METHODS: In this retrospective study, eight TGA patients with unilateral PA stenosis underwent heart catheterization and cardiac magnetic resonance (CMR) imaging. RV pressures, RV afterload (arterial elastance [Ea]), PA compliance, RV contractility (end-systolic elastance [Ees]), RV-to-PA (RV-PA) coupling (Ees/Ea), and RV diastolic stiffness (end-diastolic elastance [Eed]) were analyzed and compared to normal values from the literature. RESULTS: In all TGA patients (mean age 12 ± 3 years), RV afterload (Ea) and RV pressures were increased whereas PA compliance was reduced. RV contractility (Ees) was decreased resulting in RV-PA uncoupling. RV diastolic stiffness (Eed) was increased. CMR-derived RV volumes, mass, and ejection fraction were preserved. CONCLUSION: Unilateral PA stenosis results in an increased RV afterload in TGA patients after ASO. RV remodeling and function remain within normal limits when analyzed by CMR but RV pressure-volume loop analysis shows impaired RV diastolic stiffness and RV contractility leading to RV-PA uncoupling.

Navigating the spectrum of double-outlet right ventricle presentations: Outcomes from a contemporary cohort based on subtypes.

PURPOSE: Our aim in this study was to investigate the prenatal and postnatal prognosis of double outlet right ventricle (DORV) cases diagnosed prenatally by analyzing the outcomes based on the subtype. METHODS: This study is a retrospective chart review. Cases diagnosed with fetal DORV by prenatal ultrasound in the maternal-fetal medicine department of our hospital between 2014 and 2022 were included. Data on maternal characteristics, fetal echocardiographic features (type of DORV), pregnancy and neonatal outcomes (termination of pregnancy [TOP], intrauterine fetal death [IUD], neonatal death [NND], death in infancy (IND), survival) were collected and analyzed. RESULTS: Ninety-nine cases of prenatally diagnosed cases of DORV were included. The prenatal diagnosis was right in 97% of the liveborn fetuses. The cases were classified into subtypes, including transposition of great arteries (TGA), Fallot, ventricular septal defect (VSD), remote, and heterotaxy types. The cohort consisted of 32.3% TGA type, 19.1% fallot type, 11.1% VSD type, 2% remote type, and 35.3% heterotaxy type of DORV. An additional cardiac anomaly was observed in 87% and an extra-cardiac anomaly was observed in 54% of the cases. When we excluded the cases with heterotaxy type but without any chromosomal abnormality, additional genetic abnormalities were detected in 42% of the remaining cases. Outcome of pregnancy was livebirth in 68/99 (68.7%), IUFD in 5/99 (5.1%), and TOP in 26/99 (26.3%). Postnatal cardiac surgical repair was performed in 48 cases. Survival among livebirths was 39/68 (57.3%). Twenty-nine neonates or infants who had additional cardiac anomalies and/or genetic abnormalities died before any surgical intervention. The postoperative survival rate was 39/48 (81.2%). CONCLUSION: The prognosis in DORV depends on the anatomical subtype, the presence, and severity of associated anomalies. Survival increases in isolated cases without any additional structural or genetic anomalies.